The original/previous design of this model. Long before Quilter, Milkman, neodynium speakers, class D power amps, and the link, there were various attempts to make compact solid-state amps that could keep up with a decent stage volume without taking up your entire back seat and without breaking your back. While this amp might be on the heavy side by today's standards, it's compact design as actually quite reasonable for it's day and it really works well as a jazz amp. Despite it's compact size, the speaker response is cable of deep resonant lows, making it an amp favored by extended range and 7+ string players. In addition to your typical Bass and Treble controls, this amp also has a "Body" control which adds overall sonic information to your signal, and "scruff" which seems to add some grit to the tone, though it is currently intermittent on this unit. The amp also has switches for "depth" and "expand" which alter some of the subtle characteristics of the equalization spectra. Comes with a vinyl slip cover.